scope:

Preface

There have been many interesting developments in the design of mechanical, plumbing, and electrical systems for earthquakes since publication of the first edition of this manual in 1999. Information from these developments has been used to revise some parts of this book and to add new material of interest to design engineers, contractors, owners, code enforcement agencies, and equipment manufacturers.

Included in Chapter 2 of this second edition are updated summaries of the 2009 International Building Code^® (IBC^®) and the American Society of Civil Engineers' (ASCE) Standard ASCE 7-10 design requirements. Also included is a summary of additional requirements from the 2010 California Building Code (CBC). In all cases, the focus on differential system displacement is highlighted.

There are updates to the specification considerations, seismic restraint devices and connection methods, and equations for seismic wind force determination along with examples. There is also a chapter that includes photographs of correct and incorrect methods for installation of mechanical, electrical, and plumbing equipment and piping.

An important addition is the information on equipment certification in Chapter 4. In the first edition, this chapter was limited to a discussion of equipment ruggedness from a nuclear industry study and some information on shipping fragility and test methods. This information has for the most part been deleted. A summary of industry standard fragility levels has been retained as a useful general reference. But the additional information on equipment shake table testing and equipment certification may be of particular value to equipment manufacturers, who may be struggling with meeting equipment certification requirements and confused over the options of analysis, testing, or experience data.

Although the testing and analysis of equipment is important, current equipment certification standards do not address piping connections. In an earthquake, the piping connected to equipment can be subject to differential displacement, straining and rupturing vulnerable piping connections. Broken piping connections were to blame for many instances of equipment shutdown in an earthquake. Accordingly, new codes require system design to accommodate differential displacements. This second edition includes valuable new information on the advantages of different types of flexible connectors, the importance of proper connector orientation, and the need for flexible connector testing to develop accurate stiffness at operating pressure.

In Chapter 5 of the first edition, we noted that concrete anchor values were easily obtainable from ICBO reports where, with a few adjustments for spacing and edge distance, most engineers could comfortably select anchor bolts. Since that time, we have learned of the critical importance of cracked-concrete testing of anchors and complex calculations to determine various anchor failure modes. Included in the second edition are illustrations and descriptions of anchors with cracked-concrete testing and a table of allowable loads for reference.

We believe this guide remains pertinent for the design engineer, installing contractors, code officials, local inspectors, and others who are interested in seismic and wind restraint design. Although this publication is considered a design guide, it should be understood that the information it presents reflects our understanding of the current code requirements and generally accepted good engineering practices. The responsibility for satisfying local codes and regulations still remains with the design professional.